Will the criminal cases brought by the United States against cyberlocker services stop at MegaUpload? Or are there more coming?Photo by Greg Sandoval/CNET

Which cyberlocker service is next to get busted?

That's one of the questions that have lingered since the January 19 raid on the home of Kim DotCom, the founder of MegaUpload. Two of that company's rivals, RapidShare and MediaFire, appear to be trying to make sure that it's not them. They are speaking out publicly now in an effort to show the differences between their services and rivals, especially MegaUpload. Cyberlock services enable people to store their digital media on a third-party's servers.

Danny Raimer, RapidShare's general counsel, told U.S. News & World Report that Megaupload's approach to piracy was "so far from what we're doing and what we want to stand for."

Ira Rothken, MegaUpload's attorney wasn't immediately available for comment. But copyright owners in the music and film industries told CNET today that they're underwhelmed by both companies' "public relations efforts."

Three months ago, the U.S. Attorney shut down MegaUpload's service, indicted managers, and had them arrested in New Zealand. The U.S. government seeks to extradite the group to the United States for trial. In the aftermath, much of the cyberlocker community got spooked. Roughly a dozen services either quickly altered their sites to rid them of pirated music, movies, and other content, or closed up shop altogether.

Yesterday, RapidShare, which has for years denied violating copyright laws, took its case to the Washington, D.C., press. The company released a "responsible practices" manifesto for cloud storage companies (the blog TorrentFreak has a copy). Those include booting chronic infringers, requiring valid e-mail, and posting in the TOS the company's right to inspect the lockers of repeat infringers for copyrighted content.

In MediaFire's case, the company responded three weeks ago to allegations made by Alfred Perry, an executive from Paramount Pictures film studio, that the service was a "rogue" site. Perry cranked up the speculation about the possibility of more police raids when he said during a panel discussion in New York a few weeks ago that the film studios "continue to make criminal referrals."

Paramount Pictures alleges that companies on this list are the top five 5 'rogue' cyberlocker services.Photo by Greg Sandoval/CNET

Perry didn't say which "rogue" cyberlocker services the movie studios had referred to law enforcement officials, but he did give CNET a graphic which listed five companies, including PutLocker, Wupload, and MediaFire.

Tom Langridge, one of MediaFire's co-founders, wrote a note to CNET listing all the ways MediaFire protects copyrighted materials, which include not paying people to upload -- a practice that experts say encourages people to store pirated movies, TV shows, and films in their lockers so they can be accessed by the masses.

Langridge wrote: "MediaFire cooperates fully with the MPAA, RIAA, and various other organizations who work to identify and prohibit the distribution of copyrighted content."

A representative from the Motion Picture Association of America (MPAA), the trade group for the six Hollywood film studios, declined to comment about RapidShare or MediaFire. A spokesman for the top four recording companies did likewise for MediaFire but issued a statement about RapidShare.

We welcome the fact that RapidShare recognizes that its service is used as an illegal distribution hub for copyrighted material and that it has a shared responsibility to prevent this theft. Its actions signify a commendable step forward. Unfortunately the new measures announced fall short if the goal is indeed to meaningfully and effectively reduce the massive amount of copyright theft occurring on its service. This is not a debate about a particular technology - legitimate cloud-based services have many beneficial uses - this is about a particular business model. For example, while other file-hosting services provide secure storage for users' files, RapidShare allows unlimited distribution of copyrighted files among millions of anonymous strangers without taking adequate steps to prevent this illegal activity.

Film industry sources say the studios think RapidShare is being disingenuous. For a long time the company has refused to implement a filtering technology similar to the one employed by YouTube, which prevents flagged copyrighted video clips from being re-posted to the service.

The sources also said that Perry wasn't bluffing. The studios have complained about specific cyberlockers to the law enforcement. But it's important to note that there's no telling whether the government is investigating or will take any action in the future. It's not even certain that if the government pursued criminal actions against the cyberlockers whether it could win convictions.

Numerous copyright lawyers have noted that the government's arguments in the MegaUpload case appear to be breaking new ground.

The test case will likely be MegaUpload, and the company isn't lying down. Rothken, a U.S. attorney and the man in charge of the company's worldwide defense, has hired some well-known lawyers in different countries.

Recently, Rothken hired Quinn Emmanuel, and the defense team in this country will include William Burck, the former special counsel and deputy counsel to President George W. Bush, and Andrew Schapiro, the attorney who helped defend YouTube in the copyright case brought against the company by Paramount Pictures parent Viacom.